You may copy Opt-Outs to your SUPPRESS account that come in to your MailChimp account in real time. 

First, you will need to generate an opt-out link from SUPPRESS that feeds unsubscribes to your desired list stored in SUPPRESS. You can do so by either accessing an existing campaign, or creating a new one. If needed, please see:  Where I can find the Opt-Out Link? ,for help generating an Opt-Out Link.

In MailChimp: 

1. Navigate to the desired list you have setup in MailChimp and select Webhook
2. Add this endpoint: https://temp.mailchimp.api.optizmo.com/+{opt-out key}
3. Replace “+{opt-out key} with the opt-out link key from your system.  Below is an example 

4. Then select “unsubscribes” for the data type to be sent over and save the settings.